Expansion grate for incinerator

ABSTRACT

An incinerator including a combustion chamber is provided wherein an expansion grate is disposed proximate the entrance to the combustion chamber. The expansion grate is movable between an extended position in which the amount of combustible materials which may be deposited within the incinerator is limited and a retracted position in which the combustible materials fall to the bottom of the combustion chamber for incineration. The incinerator also includes a mechanically interconnected loading door and combustion chamber access cover. When it is desired to load the combustion chamber with combustible materials, the expansion grate is placed in its extended position and the loading door and access cover are opened. As long as the expansion grate is not retracted, the loading door and access cover may be opened repeatedly to deposit more combustible materials. However, when the expansion grate is retracted, an interlock means and locking means combine to keep the loading door locked until an incineration cycle is completed. Thus, it is impossible to overload the combustion chamber with combustible materials or to open the loading door during the incineration cycle.

United States Patent [1 1 Eff [ EXPANSION GRATE FOR INCINERATORChristian A. Eff, Louisville, Ky.

[73] Assignee: General Electric Company,

Louisville, Ky.

[22] Filed: June 20, 1974 [21] Appl. No.: 481,103

[75] Inventor:

2,783,723 3/1957 Loewenthal et a1. 110/18 3,467,035 9/1969 Anderson eta1. 1lO/l8 3,742,874 7/1973 Eff l10/8 Primary Examiner-Kenneth W.Sprague 57] ABSTRACT An incinerator including a combustion chamber is [41 May 13,1975

provided wherein an expansion grate is disposed proximate the entranceto the combustion chamber. The expansion grate is movable between anextended position in which the amount of combustible materials which maybe deposited within the incinerator is limited and a retracted positionin which the combustible materials fall to the bottom of the combustionchamber for incineration. The incinerator also includes a mechanicallyinterconnected loading door and combustion chamber access cover. When itis desired to load the combustion chamber with combustible materials,the expansion grate is placed in its extended position and the loadingdoor and access cover are opened. As long as the expansion grate is notretracted, the loading door and access cover may be opened repeatedly todeposit more combustible materials. However, when the expansion grate isretracted, an interlock means and locking means combine to keep theloading door locked until an incineration cycle is completed. Thus, itis impossible to overload the combustion chamber with combustiblematerials or to open the loading door during the incineration cycle.

8 Claims, 4 Drawing Figures FATENTEU my 1 3197s SHEET 2 OF 3 F'IG.Z

PATENTED MAY 1 3 I975 SHEEI 30? 3 EXPANSION GRATE FOR INCINERATORBACKGROUND OF THE INVENTION The invention relates to incinerators and,more particularly, to an improved expansion grate disposed within thecombustion chamber of an incinerator for limiting the amount ofcombustible materials which may be placed within the combustion chamberand to interlock means for preventing improper operation of theincinerator.

A problem in incinerators is overloading of the combustion chamber. Thismay be a serious problem since an overloaded or tightly packedcombustion chamber may result in poor combustion, large carbon massesthat are impossible to burn, increased time for complete incineration,and localized hot spots within the combustion chamber. Additionally, ifan agitator is provided to stir combustible materials, overloading ofthe combustion chamber may cause jamming of the agitator with resultantdamage thereto.

A further problem arising through overloading of the combustion chamberis that combustible materials placed in the combustion chamber maycontact heating units for the combustion chamber, resulting ininefficiency, overheating, or damage to the heating units. If thecombustible materials have been tightly packed within the combustionchamber, forces may be transmitted from the agitator through thecombustible materials to the heating units, resulting in damage to theheating units.

In view of the above-mentioned problems, it is an object of the presentinvention to prevent the overloading of the combustion chamber of anincinerator and thus avoid the problems of unburned carbon masses,combustion inefficiency, increased incineration times, and localized hotspots within the combustion chamber.

It is another object of the invention to prevent jamming of an agitatordisposed within the combustion chamber of an incinerator due tooverloading the combustion chamber and thus avoid damage to theagitator.

It is a further object of the invention to prevent improper operation ofthe incinerator by the user.

SUMMARY OF THE INVENTION In carrying out the invention, in one formthereof, an incinerator including a combustion chamber is providedwherein an expansion grate is disposed proximate the entrance to thecombustion chamber. The expansion grate is movable between a first orextended position in which the amount of combustible materials which maybe deposited within the incinerator is limited and a second or retractedposition in which the combustible materials fall to the bottom of thecombustion chamber for incineration. When it is desired to load thecombustion chamber with combustible materials, the expansion grate isplaced in its extended position and the loading door and access coverare opened. As long as the expansion grate is not retracted, the loadingdoor may be opened repeatedly to deposit more combustible materials.However, when the expansion grate is retracted, an interlock means andlocking means combine to keep the loading door locked until anincineration cycle is completed. Thus, it is impossible to overload thecombustion chamber with combustible materials or to open the loadingdoor during the incineration cycle.

.DESCRIPTION OF THE DRAWINGS FIG. 1 is a right side, cross-sectional,elevational view of an incinerator according to the invention showing aloading door and access cover in a closed position and showing in solidlines and dotted lines an expansion grate in extended and retractedpositions, respectively.

FIG. 2 is a plan view of an incinerator according to the invention takenalong line 2-2 of FIG. 1 and showing an arm and hinge means for theexpansion grate.

FIG. 3 is a schematic circuit showing the interlock means and lockingmeans of the present invention.

FIG. 4 is a fragmentary schematic drawing of the locking means for theloading door.

DESCRIPTION OF THE INVENTION The present invention deals with animproved incinerator structure. The description in the presentapplication is directed only to those portions of the overallincinerator structure which comprise the present invention. For a morecomplete description of the basic incinerator structure with which thepresent invention is employed, reference may be had to two prior patentsissued to the assignee of the present invention, U.S. Pat. No.3,742,874, Solid Waste Incinerator, and U.S. Pat. No. 3,788,243,Domestic Solid Waste Incinerator.

Referring to FIGS. 1 and 2, there is shown an incinerator 10.Incinerator 10 includes an outer incinerator housing 12 of sheet metal,box-like construction that defines the outer limits of the incineratorand forms a supporting structure for the operational components of theincinerator. It will be appreciated that an incinerator is a hightemperature device reaching temperatures above 1500F in some areas andthat thermal insulating means must be provided within housing 12 toinsure that the external surface temperatures of the incinerator arekept low. An air space 11 is formed interiorly of each outer wall ofhousing 12 by means of an insulation wall 14 spaced from housing 12 andwhich insulation wall has associated therewith a layer of thermalinsulation 13.

The incinerator includes a combustion chamber 20 formed by an innerliner 22. The inner liner 22 has a forwardly inclined, semicylindricalfront wall 26 with a bottom wall 28, a generally vertical rear wall 30,and a top wall 32 having a downwardly inclined front portion 33. Anaccess cover 34, which provides for loading the incinerator withcombustible materials through a loading door 36, cooperates with anopening 35 in the inclined front portion 33. Moreover, access cover 34is provided with a sealing gasket 38 which is adapted to be compressedtightly against the peripheral flange of opening 35 for rendering thecombustion chamber 20 generally airtight and precluding the escape ofheated gases, smoke, odors, vapors, and the like. Loading door 36 andaccess cover 34 are integrated to move together by a suitable mechanicallinkage 40 so that they can be moved with one hand, leaving the otherhand free to deposit combustible materials through opening 35.

It is possible to locate the incinerator heating means so that theheating means are in direct contact with the combustible materials. Theheating means could be located within combustion chamber 20 adjacent thetop of inner liner 22 and away from opening 35. However, it has beendeemed preferable to locate the heating means in the form of aresistance heating element 41,

shown schematically in FIG. 3, in the main heater compartment 42 whichis positioned at the front of the incinerator housing generally beneaththe forwardly inclined, semi-cylindrical front wall 26 of inner liner22.

Combustion chamber includes an agitator 44 disposed in the lower portionthereof, directly above bottom wall 28. Agitator 44 is driven by a shaft46, which shaft is in turn driven by an agitator motor 48. Agitatormotor 48 is not shown in FIG. 1 since it is disposed within a housing50. However, agitator motor 48 is shown schematically in FIG. 3.

Further included within combustion chamber 20 is an expansion grate 52.Expansion grate 52 is comprised of a short, flat portion 54, which flatportion is hingeably mounted at one end to downwardly inclined frontportion 33 of top wall 32 by a hinge means 56. Expansion grate 52 alsocomprises a downwardly extending portion 58 of spaced parallel barshaving a semicylindrical end portion 60, which end portion mates withthe inner liner 22 when expansion grate 52 is in its extended positionas shown by the solid lines in FIG. 1. In its extended position thegrate 52 defines a loading chamber 61 into which combustible materialsmay be deposited. The size of the loading chamber 61, relative to thesize of full combustion chamber 20 available when the grate is in itsretracted position, insures that the combustible material will not betightly packed in chamber 20 and combustion will be efficient. It willbe understood that expansion grate 52 could be mounted for movementwithin combustion chamber 20 by any well-known means, and hinge means 56is intended only as illustrative of one type of mounting.

In order to extend and retract expansion grate 52, an actuatingmechanism is included therewith. The actuating mechanism comprises anarm 62 having a handle 64 at the outer end thereof. Both expansion grate52 and arm 62 are rigidly affixed to hinge means 56 so that for everymovement of arm 62 there is a corresponding movement of expansion grate52. Handle 64 extends beyond housing 12 so that the operator may extendor retract expansion grate 52 from outside the incinerator housing. Asshown in FIG. 1, when expansion grate 52 is in its first or extendingposition as shown by the solid lines, arm 62 and handle 64 are in theirraised positions as shown by the solid lines. Conversely, when expansiongrate 52 is in its second or retracted position as shown by the dottedlines, arm 62 and handle 64 are in their lowered positions as shown bythe dotted lines.

In order to prevent overloading of combustion chamber 20 and to preventloading door 36 from being opened until after an incineration cycle hasbeen completed, an interlock means 66 and locking means 68 are providedto lock loading door 36 once expansion grate 52 has been retracted.Referring to FIG. 3, interlock means 66 and locking means 68 are shownas part of a schematic representation of the electrical circuitry of theincinerator.

Interlock means 66 comprises, in part, an interlock thermostat 70connected across line L and grounded neutral connector N, whichinterlock thermostat includes a normally closed switch 72 and a normallyopen switch 74. If the temperature within combustion chamber 20 shouldrise above a predetermined temperature, such as approximately l40F,switch 72 is opened and switch 74 is closed. Interlock means 66 furthercomprises a door interlock switch 76 in series with line L an expansiongrate interlock switch 78 in series with line L and a normally closedswitch 80 connected across line L, and grounded neutral connector Nthrough interlock thermostat 70.

In order to actuate switches 76, 78, and 80, an actuating system isprovided. Referring to FIG. 1, the actuating system for door interlockswitch 76 comprises a push rod 82 disposed near the top portion of theincinerator, which push rod extends from switch 76 to door 36. Push rod82 is supported by a pair of guides 84 and includes a stop 86 rigidlyaffixed thereto. A spring 88 is disposed intermediate stop 86 and one ofthe guides 84. Push rod 82 is axially translated upon the opening orclosing of loading door 36 and this in turn actuates switch 76. Switch76 is closed when loading door 36 is closed and is opened when loadingdoor 36 is opened. Similarly, the actuating mechanism for switches 78and 80 comprises a push rod 90, guides 92, and spring 96. Push rod 90 istranslated in response to movements of arm 62 such that switch 78 isclosed when expansion grate 52 is retracted and is opened when expansiongrate 52 is extended. Switch 80 is also actuated in response tomovements of the push rod 90, except that switch 80 is open when switch78 is closed and vice versa.

Referring to FIGS. 1, 3 and 4, the locking means 68 includes a lockingbolt 98 having a tab 100 at one end thereof. The tab is arranged forengaging a slot 102 in loading door 36 to lock the door. As most clearlyshown in FIG. 4, the locking bolt 98 is mounted on a pivot 104 and isbiased toward its locking position by a spring 106. A solenoid 108, whenenergized, causes the locking bolt 98 to move counterclockwise to asufficient extent to allow the tab 100 to clear the upper end of thedoor 36. When the door is in its closed position and the solenoid isde-energized, the tab 100 falls into the slot 102 in the door to lockthe door in its closed position.

The solenoid 108 is momentarily energized for actuation of the lockingbolt 98 by a momentary contact switch 110. The switch 110 and thesolenoid 108 are connected between line L and grounded neutral connectorN in series with interlock thermostat 70 and switch 80.

A second pivoted locking bolt 112, shown schematically in FIGS. 2 and 3,is arranged for engaging openings in side extensions of arm 62 to lockthe arm and its associated expansion grate 52 in position. Specifically,the extensions 114 and 116 (shown also in FIG. 1) of arm 62 includeopenings 118 and 120, respectively. The locking bolt 112 includes a tab122 at one end which is arranged to be received in opening 120 forholding the arm 62 in its upper position which corresponds to theextended position of the expansion grate 52. The arm 62 is locked in itslower position, corresponding to the retracted position of the expansiongrate, by engagement of the tab 122 with the opening 118 in armextension 114.

A solenoid 126 is provided for effecting release of the second lockingbolt 112. A spring 125 normally pivots the locking bolt 112 intoengagement with the holes 118 or 120 of the side extensions 114 and 116.This solenoid is energized by means of a momentary contact switch 128 tocounteract the action of the spring 125. The switch 128 and the solenoid126 are connected to line L, through door interlock switch 76 andgrounded neutral connector N through contacts 72 in the interlockthermostat 70. Thus, momentary actuation of switch 128, which is springbiased to its open position, effects energization of solenoid 126 tocause counterclockwise movement of the locking bolt 112 and retract thetab 122 of second locking bolt 110 from engagement with one of theopenings 118 or 120 to permit movement of the arm 62 and expansion grate52.

The circuit for solenoid 126 includes interlock thermostat 70 so that solong as switch 72 is open (that is, when incinerator temperature is over140F) the solenoid 126 cannot be energized by closing switch 128 and thearm 62 cannot be shifted from its lower (or dotted line position inFIG. 1) position and the expansion grate 52 is retained in its second orretracted position.

OPERATION It will be assumed that an incineration cycle has beencompleted and that it is desired to load the combustion chamber withmore combustible materials prior to initiating another incinerationcycle. It will be assumed further that the temperature within combustionchamber 20 has fallen below approximately 140F so that switch 72 isclosed and switch 74 is open. Switch 76 is closed since loading door 36is closed; also, switch 78 is closed and switch 80 is open sinceexpansion grate 52 is in its retractedposition. Before the loading door36 can be opened for deposition of combustible materials withincombustion chamber 20, expansion grate 52 must be moved to its extendedposition by means of the handle 64.'Moving the grate to its extendedposition closes switch 80. With switch 80 closed, solenoid 108 may beenergized by pushing momentary contact switch .110, thereby moving tab100 of locking bolt 98 out of slot 102 in loading door 36. This permitsloading door 36 to be opened and combustible materials to be depositedin the incinerator.

Referring particularly to FIG. 4, it will be seen, once door 36 isopened, tab 100 of locking bolt 98 cannot engage slot 102 until solenoid108 is again energized. Thus, the operator may repeatedly deposit morecombustible materials until the chamber defined by expansion grate 52 isfull, merely by opening and closing loading door 36 without pushingmomentary contact switch 110. Since solenoid 108 must be energized tolock or unlock loading door 36, door 36 is in a so-called almost closedcondition (as shown in FIG. 4) after it has been unlocked upon thecompletion of an incineration cycle.

It will now be assumed that the operator desires to initiate anotherincineration cycle. Referring to FIG. 3, it is seen that both switches76 and 78 must be closed in order to permit electrical current to flowto the electrical components of the incinerator. This can beaccomplished only by both closing loading door 36 and retractingexpansion grate 52. When expansion grate 52 is moved to its retractedposition, any previously deposited combustible materials fall to thebottom of combustion chamber 20. However, since the materials will nowoccupy a greater volume due to the retraction of expansion grate 52,combustion will be very efficient.

Once incineration has commenced and the temperature within combustionchamber 20 has exceeded appoximately 140F, it will be impossible for theoperator to overload combustion chamber 20 by depositing morecombustible material in the incinerator. This is because interlockthermostat 70 causes normally open switch 74 to close and normallyclosed switch 72 to open when the temperature reaches F, therebypreventing thecompletion of a circuit through switch 128 and solenoid126. Thus, solenoid 126 cannot be energized to move the bolt 112 out ofengagement with opening 118 and permit the handle 64 to be raised andthe expansion grate 52 to be moved to its extended position until switch72 is caused to close by the lowering of the temperature withincombustion chamber 20 below 140F. After the incinerator has cooled below140F, expansion grate 52 may be extended and thereafter loading door 36may be opened.

Many advantages result from the use of the present invention. Forexample, the present invention eliminates the problem of large unburnedcarbon masses and localized hot spots. Additionally, jamming of agitator44 with resultant damage to agitator 44 is no longer a problem since itis impossible for the operator to tightly pack combustible materialsagainst agitator 44. A further advantage of the present invention isthat if it were desired to locate. heating elements adjacent back wall30, the heating elements would be protected from direct contact withcombustible materials by portion 58 of expansion grate 52. Thus, forcescannot be transmitted from agitator 44 through the combustible materialsto the heating elements nor could damage to the heating elements occurthrough direct contact with combustible materials during incineration.

The interlock means and locking means of the present invention serve toprevent the operator from loading the loading chamber, retractingexpansion grate 52, and then once again extending expansion grate 52 inorder to load more combustible materials into loading chamber 61. Thisis so, even at temperatures below about 140F, because the presence ofthe first load that had been dumped would prevent the grate from beingextended back into the full line position of FIG. 1. Moreover, sinceexpansion grate 52 must be extended before loading door 36 is unlockedafter an incineration cycle, the chances of a fire occurring due to theoperator dropping additional combustible materials to the bottom ofcombustion chamber 20 are eliminated. This is because contact betweenadditional combustible materials and any hot ash remaining in the bottomof combustion chamber 20 after the completion of an incineration cycleis precluded by the extended expansion grate. Thus, the presentinvention permits maximum utilization of the incinerator in that theoperator may repeatedly load loading chamber 61 with combustiblematerials until it is full; further, the present invention solves all ofthe previously mentioned problems of incinerators resulting fromoverloading of the combustion chamber; and still further, by utilizingan interlock means and locking means, the present invention prevents theoperator from defeating the purpose of the expansion grate.

Although a specific embodiment of the invention has been described, itwill be obvious to those skilled in the art that changes andmodifications may be made without departing from the invention. It istherefore intended in the appended claims to cover all such changes andmodifications that fall within the true spirit and scope of theinvention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. In an incinerator comprising a combustion chamber, a loading door forthe incinerator, and heating means for incinerating combustiblematerials disposed within the combustion chamber, the improvementcomprising:

an expansion grate disposed within said incinerator,

said expansion grate being mounted in said incinerator for movementbetween a first position in which said expansion grate defines a loadingchamber to limit the amount of combustible materials which may be placedin the incinerator and a second position in which said combustiblematerials are discharged from said loading chamber into saidincinerator.

2. The incinerator of claim 1 wherein said expansion grate is hingeablymounted for movement between said first and second positions.

3. The incinerator of claim 1 including an arm for moving said expansiongrate between its first and second positions.

4. The incinerator of claim 3 including:

a. means for locking said door in its closed position,

and

b. means for preventing the unlocking of said door until incineration iscomplete.

5. The incinerator of claim 3 including:

a. means for locking said arm in a position corresponding to the secondposition of said expansion grate, and

b. means for preventing the unlocking of said arm until incineration iscomplete.

6. The incinerator of claim 5 including:

a. a first locking bolt arranged to engage said door for locking saiddoor in its closed position,

b. a first solenoid for actuating said bolt to its unlocked position topermit opening of said door, and

c. means for preventing energization of said solenoid until theincineration is complete.

7. The incinerator of claim 6 further including:

a. a second locking bolt for locking said expansion grate in its secondposition,

b. a second solenoid for actuating said bolt to permit movement of saidexpansion grate from its second position to its first position, and

0. means for preventing energization of said solenoid until theincineratioin is complete.

8. The incinerator of claim 7 including:

a. an arm connected to said expansion grate for moving said gratebetween its first and second positions, and

b. said arm including a portion having an opening therein, said boltengaging said opening to lock said grate in the second position.

1. In an incinerator comprising a combustion chamber, a loading door forthe incinerator, and heating means for incinerating combustiblematerials disposed within the combustion chamber, the improvementcomprising: an expansion grate disposed within said incinerator, saidexpansion grate being mounted in said incinerator for movement between afirst position in which said expansion grate defines a loading chamberto limit the amount of combustible materials which may be placed in theincinerator and a second position in which said combustible materialsare discharged from said loading chamber into said incinerator.
 2. Theincinerator of claim 1 wherein said expansion grate is hingeably mountedfor movement between said first and second positions.
 3. The incineratorof claim 1 including an arm for moving said expansion grate between itsfirst and second positions.
 4. The incinerator of claim 3 including: a.means for locking said door in its closed position, and b. means forpreventing the unlocking of said door until incineration is complete. 5.The incinerator of claim 3 including: a. means for locking said arm in aposition corresponding to the second position of said expansion grate,and b. means for preventing the unlocking of said arm until incinerationis complete.
 6. The incinerator of claim 5 including: a. a first lockingbolt arranged to engage said door for locking said door in its closedposition, b. a first solenoid for actuating said bolt to its unlockedposition to permit opening of said door, and c. means for preventingenergization of said solenoid until the incineration is complete.
 7. Theincinerator of claim 6 further including: a. a second locking bolt forlocking said expansion grate in its second position, b. a secondsolenoid for actuating said bOlt to permit movement of said expansiongrate from its second position to its first position, and c. means forpreventing energization of said solenoid until the incineratioin iscomplete.
 8. The incinerator of claim 7 including: a. an arm connectedto said expansion grate for moving said grate between its first andsecond positions, and b. said arm including a portion having an openingtherein, said bolt engaging said opening to lock said grate in thesecond position.